Tractor arm



FIG. 1 is a right side view of a tractor arm showing my new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a right cross sectional view of FIG. 4 thereof;

FIG. 6 is a left cross sectional view of FIG. 4 thereof;

FIG. 7 is a top plan view of FIG. 2 thereof; and,

FIG. 8 is a bottom plan view of FIG. 2 thereof. 

The ornamental design for a tractor arm, as shown and described. 